1. Field of the Invention
This invention relates to suspension assemblies for track-type vehicles, and more particularly to a suspension assembly which enables respective front and rear sides of track frames pivotally mounted on both sides of the vehicle body to the main frame thereof to move upwards and downwards, and which can lock movements of the respective rear sides of the track frames.
2. Description of the Prior Art
As for suspension assemblies for track-type vehicles which have so far been well known and employed, there is a system (a first prior art example) wherein track frames are completely fixed to the vehicle body, another system (a second prior art example) wherein the front sides of track frames are vertically movably supported to the vehicle body through an equalizer bar and the rear sides thereof are pivotally mounted on pivot shafts extending horizontally on both sides of the vehicle body, and a further system (a third prior art example) wherein, in addition to the arrangement of the second prior art example, lower bogie wheels are resiliently supported relative to track frames.
However, the suspension assembly according to the aforementioned first prior art example is disadvantageous in that since the shock from the road surface is transmitted directly to every part thus giving less comfortable riding and reducing the durability of the component parts of the vehicle.
The suspension assembly according to the above-mentioned second prior art example has been employed in most of track-type vehicles and is considerably improved as compared with the first prior art first example, but is inferior to the third prior art example in respect of comfortableness in driving.
The aforementioned suspension assembly according to the third prior art example gives comfortable driving of the vehicle, but is complicated in construction and expensive to manufacture. Further, the vehicle body becomes unstable during operation because of running by endless track chains supported by resilient suspension wheels. Therefore, the suspension assembly of this system is disadvantageous in that it gives inferior operability.